通过初始值设定项将作用域添加到 ActiveRecord::Base

Question

我试图通过初始值设定项添加这样的范围

class ActiveRecord::Base        
  scope :this_month,  lambda { where(:created_at => Time.now.beginning_of_month..Time.now.end_of_month) }
end

但是我收到错误"NoMethodError：对象：类的未定义方法'abstract_class？正确的方法是什么？

Answer 1

您正在覆盖一个类，而您应该通过模块执行此操作。我也会对这种方法有点小心，因为您正在关注每个模型都有created_at

module ActiveRecord
  class Base
    scope :this_month,  lambda { where(:created_at => Time.now.beginning_of_month..Time.now.end_of_month) }
  end
end

Answer 2

这是一个工作版本，您可以包含在初始值设定项中，例如 app/initializer/active_record_scopes_extension.rb .

只需致电MyModel.created(DateTime.now)或MyModel.updated(3.days.ago).

module Scopes
  def self.included(base)
    base.class_eval do
      def self.created(date_start, date_end = nil)
          if date_start && date_end
            scoped(:conditions => ["#{table_name}.created_at >= ? AND #{table_name}.created_at <= ?", date_start, date_end])
          elsif date_start
            scoped(:conditions => ["#{table_name}.created_at >= ?", date_start])
          end
      end
      def self.updated(date_start, date_end = nil)
          if date_start && date_end
            scoped(:conditions => ["#{table_name}.updated_at >= ? AND #{table_name}.updated_at <= ?", date_start, date_end])
          elsif date_start
            scoped(:conditions => ["#{table_name}.updated_at >= ?", date_start])
          end
      end
    end
  end
end
ActiveRecord::Base.send(:include, Scopes)